The spectral behavior of light reflected from substrates has been long used for characterizing the substrate's characteristics in scientific, chemical, industrial and forensic applications. A spectral imaging camera and imaging spectrometers must be utilized when the polychromatic light in the 2-D field of view is measured simultaneously. There are numerous optical designs for realizing a spectral imaging camera or imaging spectrometers, such as Sagnac interferometer, Mach-Zender interferometer, Michelson interferometer, Twyman-Green interferometer, Fabry-Perot interferometer, Fourier Transform Spectrometer, dispersive spectrometers, and others. There are many optical methods to measure substrate and multiplayer thicknesses by measuring the spectrum of light reflected from a substrate. These optical methods can, in general, be divided into two categories: Ellipsometry and Spectroscopy. The main difference between Ellipsometry and Spectroscopy is that in Spectroscopy only the amplitude information of the reflected light from the measured object is processed while in Ellipsometry, the measured object is illuminated with oblique illumination and the phase information of the reflected light is processed as well. Both the Ellipsometry and Spectroscopy methods can use polychromatic light that is measured by spectrophotometers. For measuring a complete 2-D field of view of a substrate simultaneously (i.e. with no point- or line-scanning), an imaging Ellipsometry and imaging Spectroscopy should be applied.
It is therefore an object of the present invention to provide an improved optical measurement system by combining spectral imaging cameras or spectral imagers with other optical measurement systems in order to provide the capability for spectral analysis of optical systems.
It is a further object of the present invention to provide new algorithms that simplify the hardware of the spectral imaging camera and provide more data on the measured object.